Liquid composition containing polymerized chloroprene



Patented Aug. 31, 1943 UNITED STATES PATENT OFFICE LIQUID COMPOSITION CONTAINING rozmarznn cnnoaormma Alexander D. Macdonald, Maiden, Mass, assignor B. Chemical 00., Boston, Mass., a corporation of Massachusetts No Drawing! Original applicationlanuary iil,

1940, Serial No. 316,513. Divided and this application November 3, 1941, Serial No. 417,682

- Claims.

This invention relates to polymerized chloroprene and more particularly to liquid compositions prepared from malodorant-free plastic polymers of chloroprene.

This is a division of my copending application,

Serial No. 316,513, filed January 31, 1940.

Plastic polymerized chloroprene is chloroprene (also known as chloro-2-.butadiene-l,3) which has been polymerized to such an extent that it may be worked on the rolls of a rubber mill and compounded with other ingredients in a manner similar to that in which crude rubberis treated.

' so treated have stood at temperatures as high as it Such plastic polymerized chloroprene may be f'cured to a condition in which it resembles vulcanized rubber I in exhibiting essentially elastic rather than plastic properties. This curing" of plastic polymerized chloroprene, oi'ten spoken of as vulcanization, appears to be a further polymerization oi the chloroprene as distinguished from the vulcanization of rubber wherein sulphur is considered to be added to the molecule of the rubber hydrocarbon.

For many purposes the malodorant'character of commercial polymerized chloroprene was disadvantageous and to overcome this difliculty I made the invention described in United- States Letters Patent Nos; 2,067,854 and 2,107,796, which are directed to the preparation of malodorantfree plastic polymerized chloroprene from commercial polymerized chloroprene. The present invention makes it possible to prepare in advance liquid dispersions of malodorant-iree plastic polymerized chloroprene which will retain their 3% of the salt functions very satisfactorily.

I have conducted aging tests of liquid dispersions made in accordance with this invention, the results of which are given hereinbelow. I selected 105 F. as the temperature at which to conduct these tests, because liquid dispersions of poly- 1 merized chloroprene ordinarily are less stable at liquidity and tree-flowing qualities for substantial periods of time and, when occasion requires, they may quickly be associated with suitable compounding ingredients, including curing agents, depending upon the particularuse to which the liquid dispersions are to be put.

An object oI-thls invention is to provide'improved liquid compositions embodying malodorant-tree plastic polymerized chloroprene. Other objects are to provide such compositions having improved stability, that is, increased resistance to. thickening and gelling over a period of time, and which may be stored for substantial periods oi time without deterioration.

According to the present invention. the above and other objects are attained by incorporating a salt or the group consisting of sodium i'ormate (HCOONa) and sodium acetate (NaCfiOz) in the dispersion or colloidal solution of plastic polymerized chloroprene. I have found sodium acetate to be especially useful because of its availability, low cost and eflectiveness. Compositions I 9.5 mm.

elevated'temperatures, and F. represents the maximum temperature at which such dispersions ordinarily would be stored. In these tests dispersions in toluene of malodorant-free plastic polymerized chloroprene, which had been deodorized in the manner described in Patent No. 2,067,854, were prepared with a concentration of about 2 pounds or the polymerized chloroprene to the gallon of solution. In each case 3% 01 the salt was incorporated in the liquid composi tion. These compositions were then stored in a constant temperature chamber at 105 F. The following table illustrates the efllcacy of the salts coming within the scope of this'invention and shows the viscosity of the solutions at the beginning of the test and after 8 weeks constant exposure, to a temperature of 105 F. except where the composition had'gelled prior to the expiration oithe 8 weeks period.

The viscosity mentioned hereinabove refers to the number of seconds required for a steel ball of diameter) and weighing from 3.45 to 3.55 grams to drop 50 cm. through a sample of the liquid maintained at 25 C. in a glass tube of 19 mm. inside diameter.

Fromthe above test results it will be observed viscous.

that while ordinarily there was a relatively small increase of viscosity such increase is well within the limits normally to be expected from such colloidal dispersions. The above compositions after storage were all suitable for the use to which such compositions ordinarily are put.

The salt may be incorporated in the polymer-' ized chloroprene dispersion in any suitable manner. Thus, the salt in finely powdered state may be milled into the polymerized chloroprene on a suitable rubber mill. The milled material then may be sheeted, cut up into relatively small pieces, and dissolved in a suitable solvent, such as benzene, trichlorethylene, toluene, Solvesso, alone or in mixtures, or the solvent may be associated with a non-solvent such as ethyl acetate or naphtha.

Alternatively, the polymerized chloroprene may be associated with thesolvent in a Wemerant-free plastic polymerized chloroprene dispers'ed'in an organic solvent, said composition being characterized by resistance to thicke and gelling over a substantial period of time and by the presence therein of a salt of the group consisting ofsodium formate and sodium acetate.

Pfeiderer mixer and the salt added to the comable liquid diluent, or, if desired, compounding ingredients of the type well known in the art may be incorporated in the liquid dispersion.

Having described my invention, what I claim as newand desire to secure by Letters Patent of the United States is: H

1. Aliquid composition comprising malodor- 2. A liquid composition comprising maiodorant-free plastic polymerized chloropr dispersed in an organic solvent, said composition being characterized by resistance to thicke and gelling over a substantial period oi timeand by the presence therein of about 1' to 10% w of a salt of the group consisting of sodium iormate. and sodium acetate.

3.'A liquid composition comprising malodorant-free plastic polymerized chloroprene dispersed in an organic solvent, said composition being characterized by resistance to thickening and gelling over a'substantial period of time and bythe presence therein of about 3% of sodium formate (HCOONa). I

4, A liquid composition comprising malodorant-free plastic polymerized chloroprene dispersed in an organic solvent, said composition being characterized by resistance to thickenin and gelling over a substantial period of time and by the presence therein of about 3% of sodium acetate (NaCzHsOz).

5. The method of inhibiting thickening and gelling of a liquid dispersion of malodorant-free plastic polymerized chloroprene in an organic" solvent, which comprises incorporating in said dispersion asalt of the group consisting of sodium formate and sodium acetate.

ALEXANDER D. MACDONALD. 

